Prediction of Communicative Difficulty with Standard Speech Discrimination Tests.

Abstract

This study was concerned with the use of speech discrimination tests to predict communicative efficiency for normal and impaired listeners. Specifically, the purpose was to determine if recorded speech discrimination tests can predict communication efficiency as measured in either of two ways: (1) by self-assessment or (2) by objective testing of understanding in various quiet and standardized noise environments. There were four groups of adult subjects: normal hearing, flat sensorineural hearing loss, high-frequency sensorineural hearing loss, and normal hearing sensitivity but with subjective problems of hearing or understanding. Three commercially available tape recorded open-set response monosyllabic speech discrimination tests were used. Each test was presented in quiet and in noise. The 50-word and 25-word lists in both quiet and noise were scored in two ways: percentage of words correct and percentage of phonemes correct. The basic statistical procedure used was the Pearson product-moment correlation to determine the strength of the relationship of each discrimination list for each scoring condition and each of the other two tests of communicative function. All lists yielded comparable scores for normal listeners in quiet. For hearing loss subjects or noise environment, only two lists were comparable. Female voice resulted in significantly poorer scores. All lists were at least moderately correlated with the other two tests but performance on these tests could not be reliably predicted from the speech discrimination scores. Use of noise aided in identification of listening-impairment but norms need to be established. There was no clinically significant difference between 25-word and 50-word lists. Phonemic scoring appeared to offer little value for routine evaluations. This study supported the use of either CID Auditory Test W-22 or Northwestern University Auditory Test No. 6 for routine clinical use. It supported use of half-lists without restriction to specific populations. It supported the use of noise, particularly to identify normal hearing listeners who experience greater-than normal difficulty understanding in noise. It confirmed the need for establishment of norms for testing with female voice recordings and norms for testing with competing noise.